Why do footballers spit on the field? Recent study provides reason for common practice

A study has shed light on why footballers often spit on the field, a practice known as 'carb rinsing.' It's a process that involves swishing a carbohydrate-rich solution in the mouth and expelling it instead of consuming it.

Portugal icon Cristiano Ronaldo, France skipper Kylian Mbappe, and England captain Harry Kane were often seen spitting on the pitch at Euro 2024. Fans often question the reasoning behind it, but it's a technique athletes use in sports to keep energy up.

'Carb rinsing' tricks the brain into anticipating an influx of energy, which reduces fatigue and enhances performance. Ronaldo, 39, is regularly seen spitting out the solution, particularly near the end of games, and he then comes up clutch soon after.

It's an intriguing process aided by carbohydrate receptors in the mouth. They signal the brain that energy is forthcoming when activated, leading to positive motor function and perception of effort.

The International Journal of Sports Nutrition and Exercise Metabolism conducted a study into carb rinsing. It found that male athletes are less fatigued when using the practice during their events.

Football matches ordinarily last 90 minutes, which can be exhausting for players, given that they are participating in a high-intensity sport. Studies have shown that carb rinsing can improve performance by 2-3 percent.

Footballers spit the liquid out rather than swallow it to avoid gastrointestinal discomfort. If the concentrated liquid remains in the stomach for a while, symptoms such as bloating and other digestive issues could ensue.

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How long can the effects of carb rinsing last for a footballer?

Kylian Mbappe carb rinsing during France's Euro 2024 semifinal defeat to Spain.

Carb rinsing can hugely benefit footballers, as the practice can improve intense exercise for approximately 30-60 minutes. That's why it's so popular in football, given its lengthy effects and non-gastrointestinal issues.

Many players are often seen mouth-rinsing when preparing for extra time while their manager gives them orders. They are trying to maintain energy levels as they'll have to play another 30 minutes after a grueling 90-minute match.

Carb rinsing sometimes occurs during penalties, with goalkeepers perhaps looking for an extra burst of energy. Focus and energy go hand in hand in a penalty shootout situation where tension is sky-high.

The liquid swishing doesn't need to be long; athletes usually do the process for five to ten seconds. The liquids used are usually CHO solutions, either glucose or maltodextrin (MALT).